Matsui Hidenori, Fujiwara Masayuki, Hamada Satoshi, Shimamoto Ko, Nomura Yuko, Nakagami Hirofumi, Takahashi Akira, Hirochika Hirohiko
Disease-Resistant Crops Research Unit, National Institute of Agrobiological Sciences, Tsukuba 305-8602, Japan (H.M., A.T., H.H.);Plant Global Educational Project (M.F.) and Laboratory of Plant Molecular Genetics (S.H., K.S.), Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan; andPlant Proteomics Research Unit, RIKEN Center for Sustainable Resource Science, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan (Y.N., H.N.).
Disease-Resistant Crops Research Unit, National Institute of Agrobiological Sciences, Tsukuba 305-8602, Japan (H.M., A.T., H.H.);Plant Global Educational Project (M.F.) and Laboratory of Plant Molecular Genetics (S.H., K.S.), Nara Institute of Science and Technology, Ikoma, Nara 630-0101, Japan; andPlant Proteomics Research Unit, RIKEN Center for Sustainable Resource Science, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan (Y.N., H.N.)
Plant Physiol. 2014 Sep;166(1):327-36. doi: 10.1104/pp.114.243873. Epub 2014 Jun 23.
Oryza sativa Pto-interacting protein 1a (OsPti1a), an ortholog of tomato (Solanum lycopersicum) SlPti1, functions as a negative regulator of innate immunity in rice (Oryza sativa). In ospti1a mutants, the activation of immune responses, including hypersensitive response-like cell death, is caused by loss of the OsPti1a protein; however, it is as yet unclear how OsPti1a suppresses immune responses. Here, we report that OsPti1a localizes to detergent-resistant membrane fractions of the plasma membrane through lipid modification of the protein's amino terminus, which is highly conserved among Pti1 orthologs in several plant species. Importantly, mislocalization of OsPti1a after deletion of its amino terminus reduced its ability to complement the mutant phenotypes, including hypersensitive response-like cell death. Furthermore, complex formation of OsPti1a depends on its amino terminus-mediated membrane localization. Liquid chromatography-tandem mass spectrometry analysis of OsPti1a complex-interacting proteins identified several defense-related proteins. Collectively, these findings indicate that appropriate complex formation by OsPti1a at the plasma membrane is required for the negative regulation of plant immune responses in rice.
水稻（Oryza sativa）中与Pto相互作用的蛋白1a（OsPti1a）是番茄（Solanum lycopersicum）SlPti1的直系同源物，在水稻先天免疫中作为负调控因子发挥作用。在ospti1a突变体中，包括类过敏反应性细胞死亡在内的免疫反应激活是由OsPti1a蛋白缺失引起的；然而，目前尚不清楚OsPti1a如何抑制免疫反应。在此，我们报道OsPti1a通过对该蛋白氨基末端的脂质修饰定位于质膜的抗去污剂膜组分，这在几种植物物种的Pti1直系同源物中高度保守。重要的是，缺失氨基末端后OsPti1a的错误定位降低了其互补突变体表型的能力，包括类过敏反应性细胞死亡。此外，OsPti1a的复合物形成依赖于其氨基末端介导的膜定位。对OsPti1a复合物相互作用蛋白的液相色谱 - 串联质谱分析鉴定了几种与防御相关的蛋白。总体而言，这些发现表明OsPti1a在质膜上进行适当的复合物形成是水稻中植物免疫反应负调控所必需的。
